1. Field of the Invention
The present invention relates to a method for manufacturing a liquid discharge head for discharging a liquid, more specifically, to a method for manufacturing an inkjet recording head for performing recording by discharging ink onto a recording medium.
2. Description of the Related Art
As an example of a liquid discharge head, Japanese Patent Application Laid-Open No. 2006-130742 discusses a discharge head in which a substrate having an energy generating element which generates energy used for discharging ink is provided with supply ports for supplying a liquid to the energy generating element. In Japanese Patent Application Laid-Open No. 2006-130742, in order to improve liquid supply performance, small apertures that go from a part having a large volume to a surface of the substrate are provided in supply ports penetrating the substrate from a rear surface to the front surface. Each of the small apertures is separately connected to a flow path.
U.S. Pat. No. 6,534,247 discusses a method for forming supply ports on a substrate as follows. The substrate is provided with a liquid discharge port on the front surface thereof and a flow path forming member that communicates with the discharge port. Wet etching is performed part of the way from a rear surface of the substrate toward the front surface of the substrate to form a recessed portion. The recessed portion serves as a large first supply port which is a part of supply ports. Subsequently, dry etching is performed on one surface forming the recessed portion that is exposed toward the rear surface of the substrate to form a second supply port. Thus, a supply port is formed which communicates the front surface with the rear surface of the substrate.
However, in the case of where the large recessed portion serving as a part of the supply ports is formed on the substrate and then the small supply port is formed by dry etching from the rear surface of the substrate as discussed in U.S. Pat. No. 6,534,247, the following problem can arise depending on the shape of the supply ports to be formed.
Namely, variations of etching rate appear within the substrate when performing the dry etching on the substrate to form the second supply port. For example, in the case where a plurality of the second supply ports is provided on the substrate, since progress of the etching on the second supply ports varies depending on etching positions in the substrate, formation of a recessed portion may be finished at one position while a recessed portion may be in the middle of formation at another position. In this case, if the etching is continued to carry on the processing of the supply port at another position, the supply port at the one position can be processed such that a sectional area becomes larger instead of being processed in a depth direction. In such a case, volumes of the second supply ports are different from each other in the liquid discharge head, and desired supply characteristics are not obtained in some cases.